In early-treated children, HAART leads to a unique state of viral persistence whereby HIV replication is controlled solely by antiretroviral drugs wit little HIV-specific immunity (elite-treatment responders). We hypothesize that long-term early effective therapy of infants may promote a state of HIV persistence that is distinct from long-term treated adults that is comprised of negligible levels of proviral DNA, a nondetectable resting CD4+T cell latent replication-competent viral reservoir, absent residual viremia, HIV specific immune responses, immune activation and inflammation. In the context of the PHACS/AMP study, we will measure the following in a cohort of preadolescent pediatric long-term elite treatment responders: 1) Determine the long- term effects of early HAART on the size of proviral and replication-competent HIV reservoirs in perinatally HIV- infected pre-adolescents and adolescents treated from infancy, 2) Examine the long-term effects of early HAART from infancy on the dynamics of HIV persistence and immune outcomes in perinatally HIV-infected pre-adolescents and adolescents, and 3) Determine the long-term effect of early HAART on diversity of proviral and replication-competent HIV reservoirs in pre-adolescents and adolescents treated from infancy. The proposed project will improve scientific knowledge on the long-term virologic and immunologic effects of early HAART for infants who are now likely to survive to young adulthood and provide a critical framework for defining HIV CURE in clinical trials aimed at achieving HIV CURE for children and adolescents.